Our basic knowledge and understanding of the mechanism by which ethanol impairs growth is meager. The proposed preliminary research is designed to investigate the possibility that ethanol retards fetal growth by altering the physiology of Somatomedins (Sms), a family of hormonally regulated growth factors, which play a pivotal role in the process of growth and differentiation. Presently, there are few publications concerning the effect of ethanol on Sms during fetal development. Specifically, this research is designed to evaluate aspects of Sm physiology that may be vulnerable to ethanol toxicity. The parameters to be investigated include the effects of ethanol in the following: 1) the capacity of tissue to secrete Sms; 2) Sm-carrier proteins and their capacity to bind Sms; and 3) the capacity of receptors to bind Sms. The rat will be used as a model in these studies because knowledge of the rat endocrine system is extensive and because this species is also vulnerable the ethanol-induced growth retardation. In these studies, dams will be fed a liquid diet with 36% of the calories derived from ethanol. Both fetal and some maternal tissue will be analyzed to examine the effect of ethanol on the Sm system during gestation. Information derived from these studies will provide a basis for more directed analysis of the role of Sms in mediating ethanol-induced fetal growth retardation.